1. Field of the Invention
The invention relates to a color cathode ray tube (CRT) and, more particularly to the manufacturing of a luminescent screen assembly having at least one color filter.
2. Description of the Background Art
A color cathode ray tube (CRT) typically includes an electron gun, an aperture mask, and a screen. The aperture mask is interposed between the electron gun and the screen. The screen is located on an inner surface of a faceplate of the CRT tube. The aperture mask functions to direct electron beams generated in the electron gun toward appropriate color-emitting phosphors on the screen of the CRT tube.
The screen may be a luminescent screen. Luminescent screens typically comprise an array of three different color-emitting phosphors (e.g., green, blue and red) formed thereon. Each of the color-emitting phosphors is separated from another by a matrix line. The matrix lines are typically formed of a light absorbing black, inert material.
In order to enhance the color contrast of the luminescent screen, a pigment layer, or color filter, may be formed between the faceplate panel and the color-emitting phosphor. The color filter typically has a color that corresponds to the color of the color-emitting phosphor formed thereon (e.g., a red-emitting phosphor is formed on a red pigmented filter). The color filter transmits light that is within the emission spectral region of the phosphor formed thereon and absorbs ambient light in other spectral regions, providing a gain in color contrast.
After the application of the color filter, the color-emitting phosphors are typically formed using a subtractive process in which a phosphor layer is deposited on the interior of the faceplate panel, and, in a subsequent development process, select portions of the phosphor layer are removed. Unfortunately, during the phosphor formation process void formation along the edges of the phosphor lines may occur. Void formation is typically caused by a failure of portions of the phosphor coating to adhere properly to the color filter layer during the phosphor formation process. Voids resulting from such adhesion failure may result in lower light output and lower contrast performance for the luminescent screen.
Thus, a need exists for a method of forming a color filter cathode ray tube (CRT) that overcomes the above drawbacks.